Miniature tube socket



March 10, 1936. A. .1 FRANKE 2,033,765

MINIATURE TUBE SOCKET I Filed July 29, 1953 HIHII INVENTOR Mal/5r or FFfiW/i' ATTORNEY Patented Mar. 10, 19.36

UNITE stares MINIATURE TUBE SOCKET August J. Franke, Harrison, N. J., assignor to Radio Corporation of America, a. corporation of Delaware Application July 29, 1933, Serial No. 682,761

3 Claims.

My invention relates to sockets for electrical devices, and particularly to sockets for use with vacuum tubes and the like.

The usual type of socket employs flat contact springs mounted perpendicularly to the axis of a tube supported by the socket. These contacts extend outwardly and more or less radially from the center of the socket and have at their outer ends either terminal lugs or binding posts. They are fastened at their outer ends or intermediate their ends to the body of the socket, usually by riveting or the like. The socket is comparatively bulky, and is considerably larger in diameter than the tube base. Any increase in the number of contacts decreases the spacing between the contacts, increases the tendency to voltage breakdown through the base, and increases the dimculty in the assembly of the socket.

Not only has a practical limit been reached in the number of contacts which can be mounted in a conventional way in a socket of conventional size, but small sockets, only about one-half the conventional size, and having at least as many contacts as the conventional sized socket, are in commercial demand. The usual number of conventional sized contacts cannot be mounted in a conventional way on a small socket yet a corresponding reduction in size of the spring contacts will result in contacts too weak for practical use, which do not have enough contact area thus causing a high resistancecontact and heating which adversely affects the resiliency of the spring contacts, and. which ofier difiiculties in assemblyof the socket.

One object of my invention is to provide a.

simple and compact socket which is smaller than the conventional socket and yet has as many or more contacts of ample contact area which are spaced practically like the contacts on the conventio'nal socket but which nevertheless possess the electrical and mechanical properties of such a socket necessary to meet all requirements.

Another object of my invention is to provide a socket having rugged contacts which occupy less space than the contacts commonly used yet have as great or greater contact area than the conventional contacts, and by means of which the electrical connection between the contacts on the base and contacts on the socket is improved.

A further object of my invention is to provide a socket contact which is simple and inexpensive to make, and which can be secured to the socket in an improved manner.

A better understanding of my invention will behad by reference to the following specification taken in connection with the accompanying drawing, in which:

Figure 1 shows one form of socket constructed in accordance with my invention and a tube having a base for cooperating with said socket.

Figure 2 is an enlarged top view of the socket shown in Figure 1, partly broken away to show the construction of the contact members.

Figure 3 is a longitudinal section of the socket shown in Figure 1 taken along the line 3-3 of Figure 2, with some of the contacts omitted.

Figure 4 is a detailed perspective view showing a socket contact constructed in accordance with my invention.

Figure 5 is a perspective View of a blank for a socket contact made in accordance with my invention.

Figure 6 is an enlarged perspective view of details of the tube base shown in Figure 1.

In' Figure 1 is shown a vacuum tube with a base It] having radial fins or terminals H which have on their inside edges lugs l2 to which the lead wires of the tubes are attached as best shown in Figure 6. The ,base shown is more fully disclosed and is claimed in a cc-pending application of George M. Rose, Jr., Serial No. 677,777, filed June 27, 1933, and assigned to the assignee of this application.

A socket suitable for this base and constructed in accordance with my invention is shown in Figures 1, 2, and 3. This socket has an-insulating cover plate or disc I3 for shielding the socket towards the periphery of the the slots being 0 enlarged at their inner ends as at IE to permit passage of the,lugs 12 on the contact fins II when the base I0 is put in the socket.

While registry of the base with the socket may be accomplished in various ways I prefer to register the base and socket by providing nonuniform angular spacing between some of the radial slots M, as indicated at a and b in Figure 2. In this way the base cannot be placed in the socket with the terminals engaging the wrong socket contacts.

In order to facilitate the registering of the base and socket when the base is put in the socket I provide the cover plate l3 with a circular guide,

such as a flat bottomed circular depression it slightly larger than the base I!) and having a circular side wall 56', substantially perpendicular to the cover and circumscribing the outer ends of the slots M. The side wall limits lateral movement of the base pins or terminals on the cover plate, but permits free rotation of the base on the cover plate thus facilitating alignment of the terminals with the slots in the cover plate.

A contact supporting member, such as a plate or disc ll of insulating material, is mounted beneath the cover plate l3 and spaced from it by studs or collars I8. This supporting member carries the socket contacts I9 between the cover plate and the supporting member, thus fully protecting and shielding the socket contacts from injury or from being accidentally short circuited by foreign objects. These contacts H! are mounted in a circle concentric with the circular recess l6 and in registry with the slots M in the cover plate.

While the contact members may be made in various ways, I prefer to punch them from blanks and fold them to shape. The contact is made from a punched blank in the shape of a cross, such as shown in Figure 5, the extensions 20 and 2| being bent downwardly to provide legs which extend through the slots 22 and 23 provided in the supporting member IT as clearly shown in Figure 4. These legs are then curled inwardly as shown at c in Figure 2 which shows a sectional view of the contact taken at the top surface of the supporting member I? and in Figure 3 which shows a vertical cross section of a contact. This simply and securely fastens the contacts to the supporting member thus eliminating the need for riveting and like methods used in the conventional socket which methods tended to weaken the contacts. These legs also provide terminal lugs for fastening circuit connecting wires thereto thus providing a compact assembly by elimimating the need for providing the usual lug required by contacts in the conventional socket. The extensions 24 and 25 are bent upwardly to the form shown to provide contact jaws having fiat surfaces providing more'than ample contact area for receiving the contacts on the tube base.

To insure good electrical contact between the terminals on the base and the socket contacts a backing spring 21 which may be of spring steel and which is U shaped engages the jaws as shown to increase the pressure therebetween when a base contact is engaged. As most clearly shown in Figure 4, this backer spring 21 is bowed upwardly at 28 and is firmly secured to the socket contact and locked in place when the edges of the legs 20 and 2| are. curled to lock the contact in place on the supportingmember H. The bowed part is flattened against the supporting member I! forcing the legs of the spring toward each other and thus increasing the pressure exerted on the jaws 24 and 25.

In Figure 2 at "d is shown a sectional view parallel to the supporting member l1 and directly above the legs of the contact, to show the relationship of the backer spring 21 and jaws 24 and 25.

The contact which is extremely simple to make requires a very small space on the supporting member I 1. The reduced angular space required by the contact over the usual contact in the conventional socket permits the number of contacts in the conventional sized socket to be increased or the size of the socket to be materially reduced and still use the maximum number of contacts now practically possible in the usual sized socket. Since there are no radially extending portions on the contact for providing lugs and fastening means to the socket the diameter of the conventional socket can be materially reduced since a smaller diameter socket can accommodate the contacts. It is apparent that by means of my invention I provide a socket which is extremely simple in construction and very compact, and provides improved electrical connection between the contacts on the socket and base, and provides a rugged and novel contact which can be easily and cheaply made.

The embodiment of the invention illustrated and described has been selected for the purpose of setting forth the principles involved, but it will be apparent that various modifications may be made to meet diiierent conditions encountered in use, and I, therefore, intend to cover all modifications within the scope of the appended claims.

What is claimed as new is:-

1. A vacuum tube socket for receiving a vacuum tube provided with radially disposed perpendicular contact fins having connecting lugs along one edge, including in combination a cover plate having a central fiat bottomed circular depression with spaced radial slots extending inwardly from the edge of said depression for guiding the contact fins into the socket contacts, the inner ends of each slot being enlarged to permit the passage of the lugs on the fins, said depression having substantially perpendicular walls to facilitate insertion of the base by limiting the lateral movement of the base terminals with respect to the cover plate while permitting free rotation of the base, contacts on said socket beneath said cover plate and having a pair of upwardly projecting jaws provided with fiat surfaces in registry with the slots in said cover plate whereby the base contact fins inserted in said socket thru said slot will be engaged between said jaws by said flat surfaces.

-2. A vacuum tube socket for receiving a vacuum tube having radially disposed perpendicular contact fins, including in combination a cover plate provided with spaced radial slots arranged in a circle and extending toward the periphery of said cover plate, a supporting member mounted in spaced relation with said cover plate and supporting contacts between said cover plate and said supporting member, said contacts registering with said slots for engaging terminals inserted through said slots, each of said contacts having a pair of upwardly projecting jaws in registry with the radial slots in said cover plate for engaging the base contact fins and having oppos'itely disposed legs on each of said contacts extending perpendicularly through said supporting member and having the perpendicular .edges of said legs curled in toward each other to fasten said contacts to said supporting member.

3. A vacuum tube socket for receiving a vacuum tube having radially disposed contact fins on its base, including in combination a cover plate with radial slots placed in a circle for guiding the base contact fins inserted into said socket, a supporting member mounted in spaced relation with saidcover plate, contacts on said supporting member disposed between said cover plate and supporting member, each of said contacts having oppositely disposed legs extending perpendicularly through said supporting member and having the perpendicular edges of said legs curled in toward each other for securing said contacts to said supporting member and for providing terminal lugs, and having a pair of upwardly directed contact jaws having fiat surfaces registering with the slots in said cover plate whereby the base contact fins inserted in said socket thru said slots will be engaged between said jaws by said fiat surfaces, and a backing spring secured between said legs and engaging said jaws for increasing the pressure exerted between said Jaws.

AUGUST J. 

